They weren't in a room, as he had supposed. They were in a corridor. The forbidden corridor on the third floor. And now they knew why it was forbidden…
This moment has three zoom levels.
This is another one of those strange moments where you really don't look for items. This is where you get the ability to duel, once you complete the spell Alohomora. You don't get scored on it. Once you open the door you can zoom inside. There you can find the cute drooling Fluffy, The Three Headed Dog.
Nothing to do here, but you can see the dark figure of Fluffy in the back.
Fluffy is now clearly visible.
In the first zoom, you mostly just hear the fire crackling. The more you zoom in, the more you hear the snarls of Fluffy, the three headed dog.